【Map】——Map用于存储具有映射关系的数据

package com.xiaozhi.mymap;

import java.util.Iterator;
import java.util.Set;
import java.util.TreeMap;

public class Test10 {
public static void main(String[] args) {
String s="abcdefghijklabcdefghijklmnopqrstuvwxyzmnopqrstuvwxyz";
TreeMap<Character,Integer>treeMap=new TreeMap<Character, Integer>();
for(char c:s.toCharArray()){
if(treeMap.get(c)!=null)
{
treeMap.put(c, treeMap.get(c)+1);
}else{
treeMap.put(c, 1);
}
}

Set<Character>characters=treeMap.keySet();
Iterator<Character>iterator=characters.iterator();
while(iterator.hasNext())
{
char c=iterator.next();
System.out.println(c+":"+treeMap.get(c));
}
}
}